1. Field
Embodiments of the present invention relate to a wavelength converting member and a projector including the wavelength converting member.
2. Description of Related Art
In recent years, time-sharing type projectors have become popular, in which, light of a plurality of wavelengths is extracted in a time sharing manner, and the extracted light of a plurality of wavelengths is successively modulated to form and project an image.
As a light source device for such a time sharing type projector, for example, there is a known light source device that includes a light source to emit a predetermined light such as a white light and a rotating wheel (i.e., wavelength converting member) having a plurality of color filters arranged in the circumferential direction for converting the light of the light source into light of a plurality of different wavelength regions.
With such a light source device, light such as a white light emitted from the light source is allowed to incident on the rotating wheel that is spinning at a constant speed, and light of a plurality of wavelengths (e.g., a blue light, a green light, a red light) can be extracted in a time sharing manner.
Also, there has been proposed a light source device, that includes a light source, such as a semiconductor laser, configured to emit light of a single wavelength, and a rotating wheel (hereinafter may also be referred to as the “phosphor wheel”) in which a plurality of wavelength converting region each including one or more appropriate fluorescent layers arranged in a circumferential direction of the wheel in place of a plurality of color filters.
The light of a single wavelength emitted by the light source such as a semiconductor laser is allowed to incident on the phosphor wheel, then, light of a plurality of wavelengths is extracted in a time sharing manner.
However, in the light source device having such a phosphor wheel, an increase in the intensity of the light irradiated on the phosphors in order to achieve higher output increases the amount of heat generated by the phosphors that elevates the temperature of the phosphors, which may resulting in a reduction of the wavelength converting efficiency of the phosphors.
In order to cope with such a problem, a light source device including a cooling fan is proposed.
Using the cooling fan, a cooling medium (air or the like) is diagonally blown in the unevenness formed at the phosphor on the phosphor wheel to cool the cooling medium (e.g., see JP 2012-78707 A).
Further, there is also proposed a light source device realizing enhanced cooling efficiency by employing a case that stores the phosphor wheel and an air blower blowing air in the phosphor wheel (e.g., see JP 2014-92599 A).
With the light source device disclosed in JP 2012-78707 A, in addition to the light source cooling device, the phosphor wheel cooling device is also required.
Accordingly, a reduction in size of the light source device becomes difficult.
Further, manufacturing costs also increase because of an increase in the number of components.
Still further, depending on the intended use, the simple cooling of the phosphor wheel fails to allow the phosphors to exhibit sufficient light emission efficiency.
Thus, in order to secure the sufficient amount of light, it may be difficult to reduce the size of the phosphor wheel (the wavelength converting member) and a projector.
With the light source device disclosed in JP 2014-92599 A, in addition to the light source cooling device, the phosphor wheel is needed to have an air blowing device.
Further, since the case storing the phosphor wheel and the air blower is required, a reduction in size of the light source device becomes difficult, and manufacturing costs also increase because of an increase in the number of components.
Still further, depending on the intended use, the simple cooling of the phosphor wheel fails to allow the phosphors to exhibit sufficient light emission efficiency.
Thus, in order to secure the sufficient amount of light, it may be difficult to reduce the size of the phosphor wheel (the wavelength converting member) and a projector.